// npm install crypto-js
 import CryptoJS from 'crypto-js';

 // 十六位十六进制数作为密钥
 const SECRET_KEY = CryptoJS.enc.Utf8.parse("3333e6e143439161");
 // 十六位十六进制数作为密钥偏移量
 const SECRET_IV = CryptoJS.enc.Utf8.parse("e3bbe7e3ba84431a");
 
 // 类型 window.localStorage,window.sessionStorage,
 const config = {
     type: 'sessionStorage', // 本地存储类型 sessionStorage
     prefix: 'SDF_0.0.1', // 名称前缀 建议：项目名 + 项目版本
     expire: 86400, //过期时间 单位：秒
     isEncrypt: true // 默认加密 为了调试方便, 开发过程中可以不加密
 }
 
 // 判断是否支持 Storage
 export const isSupportStorage = () => {
     return (typeof (Storage) !== "undefined") ? true : false
 }
 
 // 设置 setStorage
 export const setStorage = (key, value, expire = 0) => {
     if (value === '' || value === null || value === undefined) {
         value = null;
     }
 
     if (isNaN(expire) || expire < 0) throw new Error("Expire must be a number");
 
     expire = (expire ? expire : config.expire) * 1000;
     let data = {
         value: value, // 存储值
         time: Date.now(), //存值时间戳
         expire: expire // 过期时间
     }
     
     const encryptString = config.isEncrypt 
     ? encrypt(JSON.stringify(data))
     : JSON.stringify(data);
     
     window[config.type].setItem(autoAddPrefix(key), encryptString);
 }
 
 // 获取 getStorage
 export const getStorage = (key) => {
     key = autoAddPrefix(key);
     // key 不存在判断
     if (!window[config.type].getItem(key) || JSON.stringify(window[config.type].getItem(key)) === 'null') {
         return null;
     }
 
     // 优化 持续使用中续期
     const storage = config.isEncrypt 
     ? JSON.parse(decrypt(window[config.type].getItem(key))) 
     : JSON.parse(window[config.type].getItem(key));
     
     let nowTime = Date.now();
 
     // 过期删除
     if (storage.expire && config.expire * 6000 < (nowTime - storage.time)) {
         removeStorage(key);
         return null;
     } else {
         // 未过期期间被调用 则自动续期 进行保活
         setStorage(autoRemovePrefix(key), storage.value);
         return storage.value;
     }
 }
 
 // 是否存在 hasStorage
 export const hasStorage = (key) => {
     key = autoAddPrefix(key);
     let arr = getStorageAll().filter((item)=>{
         return item.key === key;
     })
     return arr.length ? true : false;
 }
 
 // 获取所有key
 export const getStorageKeys = () => {
     let items = getStorageAll()
     let keys = []
     for (let index = 0; index < items.length; index++) {
         keys.push(items[index].key)
     }
     return keys
 }
 
 // 根据索引获取key
 export const getStorageForIndex = (index) => {
     return window[config.type].key(index)
 }
 
 // 获取localStorage长度
 export const getStorageLength = () => {
     return window[config.type].length
 }
 
 // 获取全部 getAllStorage
 export const getStorageAll = () => {
     let len = window[config.type].length // 获取长度
     let arr = new Array() // 定义数据集
     for (let i = 0; i < len; i++) {
         // 获取key 索引从0开始
         let getKey = window[config.type].key(i)
         // 获取key对应的值
         let getVal = window[config.type].getItem(getKey)
         // 放进数组
         arr[i] = {'key': getKey, 'val': getVal,}
     }
     return arr
 }
 
 // 删除 removeStorage
 export const removeStorage = (key) => {
     window[config.type].removeItem(autoAddPrefix(key));
 }
 
 // 清空 clearStorage
 export const clearStorage = () => {
     window[config.type].clear();
 }
 
 // 名称前自动添加前缀
 const autoAddPrefix = (key) => {
     const prefix = config.prefix ? config.prefix + '_' : '';
     return  prefix + key;
 }
 
 // 移除已添加的前缀
 const autoRemovePrefix = (key) => {
     const len = config.prefix ? config.prefix.length+1 : '';
     return key.substr(len)
     // const prefix = config.prefix ? config.prefix + '_' : '';
     // return  prefix + key;
 }
 
 /**
  * 加密方法
  * @param data
  * @returns {string}
  */
 const encrypt = (data) => {
     if (typeof data === "object") {
         try {
             data = JSON.stringify(data);
         } catch (error) {
             console.log("encrypt error:", error);
         }
     }
     const dataHex = CryptoJS.enc.Utf8.parse(data);
     const encrypted = CryptoJS.AES.encrypt(dataHex, SECRET_KEY, {
         iv: SECRET_IV,
         mode: CryptoJS.mode.CBC,
         padding: CryptoJS.pad.Pkcs7
     });
     return encrypted.ciphertext.toString();
 }
 
 /**
  * 解密方法
  * @param data
  * @returns {string}
  */
 const decrypt = (data) => {
     const encryptedHexStr = CryptoJS.enc.Hex.parse(data);
     const str = CryptoJS.enc.Base64.stringify(encryptedHexStr);
     const decrypt = CryptoJS.AES.decrypt(str, SECRET_KEY, {
         iv: SECRET_IV,
         mode: CryptoJS.mode.CBC,
         padding: CryptoJS.pad.Pkcs7
     });
     const decryptedStr = decrypt.toString(CryptoJS.enc.Utf8);
     return decryptedStr.toString();
 }